The present invention relates to computer data backup and recovery and particularly, but not exclusively, to apparatus, methods and systems for enacting data backup and recovery.
Typically computer networks in use today have the basic topology shown in the diagram in FIG. 1. In FIG. 1, several client workstations are connected via a network to several servers.
Users perform work on the client workstations that can communicate via a network link with the servers. Clients typically store unique user data whereas servers typically provide a common central point for some function such as shared hard disk storage, data backup storage, software applications or printer control.
There are a number of current schemes used for backing up data on the network. A first scheme is for each client to individually store data to a device such as a tape drive. Tape storage has become the preferred method of backing up information on computers due to its relatively low cost, high capacity, durability and portability. This first scheme requires each person, or each administrator, responsible for a client to be responsible for backing up the data. Also, each client requires its own backup device. A second scheme is for each client to store important data on a remote file server, where the server data is backed up at regular intervals, for example on a daily basis. Thus, if a client fails, potentially only less important information is lost. A third scheme, which is available, for example, to systems which operate under Windows NT4 and are part of an NT Domain, is that all xe2x80x98specifiedxe2x80x99 information on a client is backed up, typically overnight, to a tape drive connected to an NT server.
Known backup schemes offer relatively good protection for client data, but with a very high administration overhead. For example, if data needs to be recovered by a client, for example as a result of one or more files being xe2x80x98lostxe2x80x99 or destroyed, then the client""s owner typically needs to contact an administrator of the backup system and request a restore procedure. Typically, a restore procedure involves the backup system administrator tracking down and mounting a respective tape, on which the last backup of the lost file(s) was made, and initiating the restore procedure. While such a procedure is typically very reliable, it can be perceived as onerous on client users and backup system administrators alike.
In accordance with a first aspect, the present invention provides tape storage apparatus, comprising:
interface means for connecting the apparatus to one or more clients;
controller means for controlling the apparatus and for processing messages received from the one or more clients;
primary storage means; and
tape storage means, wherein the controller is programmed:
to process backup and restore messages received from the one or more clients respectively to backup to the primary storage means data received from the clients and to restore to said clients data from the primary storage means; and
to backup to the tape storage means, in accordance with pre-defined criteria, at least some of the data stored in the primary storage means and to restore to the primary storage means, in accordance with a respective restore message received from a client, at least some data stored in the tape storage means.
Preferably, the controller means is programmed to maintain stored on the primary storage means at least the most current version of all data received from the clients. In this way, a data restore operation can be enacted using data stored in primary storage, without needing to find and install any particular backup tape.
Preferably, the controller means is programmed to backup data stored in the primary storage means to the tape storage means independently of any messages from the clients.
In preferred embodiments, the primary storage means comprises a random access storage means such as a hard disk drive. Alternatively, the primary storage means comprises non-volatile random access memory (NV-RAM). For the latter case, however, the applicants believe that currently NV-RAM would be very prohibitively expensive compared to a hard disk drive.
In preferred embodiments, the tape storage apparatus comprises a housing configured specifically to house the controller, the interface means, the primary storage means and the tape storage means. Thus, the tape storage apparatus provides a dedicated and integrated solution to data storage and recovery. In other, less preferred embodiments, the components of the apparatus may be distributed, for example, with some of the components residing on or in other apparatus, such as a computer.
In accordance with a second aspect, the present invention provides a method of backing up to a data backup and restore apparatus attached to a network data stored in one or more clients also attached to the network, the method comprising the data backup and restore apparatus storing in primary data storage a most recent version of all data received from the clients and, from time to time, in accordance with pre-determined criteria, storing in secondary data storage at least some of the data stored in the primary data storage.
In accordance with a third aspect, the present invention provides a data storage system comprising:
a network;
tape storage apparatus; and
at least one client connected to the apparatus, the (or the at least one) client comprising client storage means and client processing means, the client processing means being programmed in accordance with pre-determined criteria to determine when data stored in the client storage means should be backed up to the tape backup apparatus.
Other aspects and embodiments of the invention will become apparent from the following description and claims.